Latent vs Active TB

When someone gets exposed to TB, one of four possible outcomes can occur: The body kills and eradicates the bacteria and…

post by Visual Epidemiology

When someone gets exposed to TB, one of four possible outcomes can occur:

The body kills and eradicates the bacteria and nothing ever happens

The body cannot control the TB and the bacteria replicate and turn into a clinical case of TB (called active TB)

The body “controls” the bacteria. Although TB is still in the person, it is not active TB (this is called latent TB)

Latent TB infection can later progress to active TB infection (typically when immune system is compromised)

What is Latent TB Infection (LTBI)?

People can be exposed to the TB bacteria, but have an immune system strong enough to contain the disease. When someone is exposed to TB but is able to contain it (i.e. the bacteria does not spread), this person is said to have latent TB. People with latent TB infection are not infectious and cannot spread TB infection to others. Also, people with latent TB infection do not feel sick and do not have any symptoms. They have the bacteria inside them, but do not have active TB disease. Though they may test positive for TB diagnostics, they are not considered a medical case of tuberculosis. However, sometimes if the body is unable to continue keeping the latent TB in check, it can eventually multiply and turn into a case of active TB.